Leslie G. Ehmann attended Benson Polytechnic High School in Portland, Oregon, joined Esco Corp. in 1936, served as an engineer and designer, and retired in 1971. He also designed lift truck components for Hyster Company. Collection includes catalogs, specifications and price lists for Esco and Hyster products, 1941-1984, including lift trucks, logging equipment, rigging equipment and swage presses; patents; and plans for an adjustable rubber coupling.

Theodore Patrick Flynn (1891-1954) was an equipment development engineer for the U.S. Forest Service, Region 6, and director of the USFS Equipment Laboratory in Portland, Oregon, 1936-1949. Collection includes biographical materials, patents, blueprints, specifications, reports, photographs, clippings, a photo album, and memorabilia regarding design of specialized equipment used in forestry and construction work, particularly for controlling forest fires.